/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.gora.persistency;

import java.util.Map;

/**
 * StatefulMap extends the Map interface to keep track of the 
 * persistency states of individual elements in the Map.  
 */
public interface StatefulMap<K, V> extends Map<K, V> {

  State getState(K key);
  
  void putState(K key, State state);

  Map<K, State> states();

  void clearStates();
  
  /**
   * Reuse will clear the map completely with states. This is different
   * from {@link #clear()} in that the latter only sets entries to deleted.
   */
  void reuse();
  
}